Summary

Although dark matter is nearly ubiquitous in our universe, finding it is extremely difficult because it interacts only through gravity or other forces too small to measure. Despite its appeal as a source of energy, no one has been able to capture or contain it. However, the presence of dark matter was necessary because its gravity helped to shape structure in the early universe. In large, collapsed regions where regular matter is located, dark matter continues to affect the motion of stars and galaxies. Randall gives a lengthy, detailed chronology of the early days of our universe and demonstrates how delicate the cosmic balance can be with radiation pushing outward and gravity pulling inward. Too much of an imbalance of these forces could cause cosmic collapse or a decoupling of the existing galactic structure. This point is referred to...